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Averages questions

Simple and weighted averages.

1. Find the average of 56, 90, 65, 71, 79, 32, 73.

  1. 53.26
  2. 67.57
  3. 66.57
  4. 64.57
Answer

C. 66.57 Sum = 466, count = 7, average = 466/7 = 66.57.

2. The average marks of 8 boys is 71 and of 6 girls is 65. What is the average of the whole class?

  1. 85.54
  2. 68.43
  3. 75.27
  4. 70.43
Answer

B. 68.43 Total = 8 × 71 + 6 × 65 = 958. Average = 958/14 = 68.43.

3. The average age of 13 students is 24 years. When the teacher's age is included, the average becomes 26.14 years. What is the teacher's age?

  1. 54 years
  2. 55 years
  3. 41 years
  4. 49 years
Answer

A. 54 years Teacher = 14 × 26.14 − 13 × 24 = 54 years.

4. What is the average of the 25 consecutive odd numbers starting from 17?

  1. 51
  2. 45
  3. 49
  4. 41
Answer

D. 41 Average of an arithmetic sequence = (first + last)/2 = (17 + 65)/2 = 41.

5. Find the average of 72, 30, 28, 67.

  1. 49.25
  2. 36.94
  3. 54.18
  4. 51.25
Answer

A. 49.25 Sum = 197, count = 4, average = 197/4 = 49.25.

6. Find the average of 68, 47, 96, 16, 89, 91.

  1. 65.83
  2. 67.83
  3. 50.87
  4. 66.83
Answer

B. 67.83 Sum = 407, count = 6, average = 407/6 = 67.83.

7. Find the average of 79, 48, 92, 61, 92.

  1. 74.4
  2. 76.4
  3. 55.8
  4. 75.4
Answer

A. 74.4 Sum = 372, count = 5, average = 372/5 = 74.4.

8. Find the average of 42, 23, 61, 92, 48, 67, 89.

  1. 60.29
  2. 58.29
  3. 72.35
  4. 48.23
Answer

A. 60.29 Sum = 422, count = 7, average = 422/7 = 60.29.

9. The average marks of 12 boys is 46 and of 12 girls is 66. What is the average of the whole class?

  1. 56
  2. 45
  3. 70
  4. 42
Answer

A. 56 Total = 12 × 46 + 12 × 66 = 1344. Average = 1344/24 = 56.

10. The average age of 26 students is 44 years. When the teacher's age is included, the average becomes 43.96 years. What is the teacher's age?

  1. 34 years
  2. 43 years
  3. 54 years
  4. 32 years
Answer

B. 43 years Teacher = 27 × 43.96 − 26 × 44 = 43 years.

11. What is the average of the 16 consecutive odd numbers starting from 49?

  1. 63
  2. 58
  3. 64
  4. 65
Answer

C. 64 Average of an arithmetic sequence = (first + last)/2 = (49 + 79)/2 = 64.

12. Find the average of 18, 58, 93, 94.

  1. 63.75
  2. 65.75
  3. 78.9
  4. 72.33
Answer

B. 65.75 Sum = 263, count = 4, average = 263/4 = 65.75.

13. Find the average of 30, 64, 79, 80, 49, 91.

  1. 67.5
  2. 49.13
  3. 78.6
  4. 65.5
Answer

D. 65.5 Sum = 393, count = 6, average = 393/6 = 65.5.

14. Find the average of 36, 74, 61, 85, 94.

  1. 70
  2. 71
  3. 53
  4. 68
Answer

A. 70 Sum = 350, count = 5, average = 350/5 = 70.

15. Find the average of 79, 24, 34, 81, 73, 88, 63.

  1. 64.14
  2. 56.83
  3. 63.14
  4. 50.51
Answer

C. 63.14 Sum = 442, count = 7, average = 442/7 = 63.14.

16. The average marks of 12 boys is 63 and of 12 girls is 76. What is the average of the whole class?

  1. 70.5
  2. 86.88
  3. 76.45
  4. 69.5
Answer

D. 69.5 Total = 12 × 63 + 12 × 76 = 1668. Average = 1668/24 = 69.5.

17. The average age of 21 students is 53 years. When the teacher's age is included, the average becomes 52.32 years. What is the teacher's age?

  1. 38 years
  2. 34 years
  3. 46 years
  4. 42 years
Answer

A. 38 years Teacher = 22 × 52.32 − 21 × 53 = 38 years.

18. What is the average of the 23 consecutive odd numbers starting from 37?

  1. 53
  2. 47
  3. 59
  4. 44
Answer

C. 59 Average of an arithmetic sequence = (first + last)/2 = (37 + 81)/2 = 59.

19. Find the average of 75, 59, 17, 47.

  1. 59.4
  2. 49.5
  3. 48.5
  4. 44.55
Answer

B. 49.5 Sum = 198, count = 4, average = 198/4 = 49.5.

20. Find the average of 21, 10, 57, 39, 70, 11.

  1. 34.67
  2. 33.67
  3. 41.6
  4. 27.74
Answer

A. 34.67 Sum = 208, count = 6, average = 208/6 = 34.67.

21. Find the average of 90, 88, 85, 42, 22.

  1. 49.05
  2. 71.94
  3. 65.4
  4. 52.32
Answer

C. 65.4 Sum = 327, count = 5, average = 327/5 = 65.4.

22. Find the average of 90, 25, 15, 93, 50, 63, 42.

  1. 68
  2. 54
  3. 55
  4. 56
Answer

B. 54 Sum = 378, count = 7, average = 378/7 = 54.

23. The average marks of 11 boys is 77 and of 8 girls is 52. What is the average of the whole class?

  1. 66.47
  2. 68.47
  3. 67.47
  4. 65.47
Answer

A. 66.47 Total = 11 × 77 + 8 × 52 = 1263. Average = 1263/19 = 66.47.

24. The average age of 23 students is 53 years. When the teacher's age is included, the average becomes 52.79 years. What is the teacher's age?

  1. 36 years
  2. 58 years
  3. 38 years
  4. 48 years
Answer

D. 48 years Teacher = 24 × 52.79 − 23 × 53 = 48 years.

25. What is the average of the 13 consecutive odd numbers starting from 57?

  1. 52
  2. 55
  3. 69
  4. 62
Answer

C. 69 Average of an arithmetic sequence = (first + last)/2 = (57 + 81)/2 = 69.

26. Find the average of 50, 25, 84, 17.

  1. 33
  2. 43
  3. 35
  4. 44
Answer

D. 44 Sum = 176, count = 4, average = 176/4 = 44.

27. Find the average of 47, 30, 99, 10, 43, 32.

  1. 34.8
  2. 32.63
  3. 39.15
  4. 43.5
Answer

D. 43.5 Sum = 261, count = 6, average = 261/6 = 43.5.

28. Find the average of 29, 86, 70, 80, 33, 76, 46.

  1. 62
  2. 75
  3. 48
  4. 60
Answer

D. 60 Sum = 420, count = 7, average = 420/7 = 60.

29. The average marks of 9 boys is 68 and of 9 girls is 40. What is the average of the whole class?

  1. 59
  2. 68
  3. 41
  4. 54
Answer

D. 54 Total = 9 × 68 + 9 × 40 = 972. Average = 972/18 = 54.

30. The average age of 31 students is 42 years. When the teacher's age is included, the average becomes 42.78 years. What is the teacher's age?

  1. 67 years
  2. 50 years
  3. 60 years
  4. 74 years
Answer

A. 67 years Teacher = 32 × 42.78 − 31 × 42 = 67 years.

31. What is the average of the 24 consecutive odd numbers starting from 1?

  1. 26
  2. 24
  3. 18
  4. 29
Answer

B. 24 Average of an arithmetic sequence = (first + last)/2 = (1 + 47)/2 = 24.

32. Find the average of 50, 35, 55, 46.

  1. 46.5
  2. 37.2
  3. 55.8
  4. 34.88
Answer

A. 46.5 Sum = 186, count = 4, average = 186/4 = 46.5.

33. Find the average of 90, 33, 49, 98, 65, 97.

  1. 71
  2. 72
  3. 79
  4. 74
Answer

B. 72 Sum = 432, count = 6, average = 432/6 = 72.

34. Find the average of 76, 75, 49, 90, 55, 20, 21.

  1. 55.14
  2. 66.17
  3. 56.14
  4. 54.14
Answer

A. 55.14 Sum = 386, count = 7, average = 386/7 = 55.14.

35. The average marks of 10 boys is 42 and of 11 girls is 74. What is the average of the whole class?

  1. 60.76
  2. 59.76
  3. 64.64
  4. 58.76
Answer

D. 58.76 Total = 10 × 42 + 11 × 74 = 1234. Average = 1234/21 = 58.76.

36. The average age of 40 students is 36 years. When the teacher's age is included, the average becomes 36.83 years. What is the teacher's age?

  1. 71 years
  2. 70 years
  3. 72 years
  4. 53 years
Answer

B. 70 years Teacher = 41 × 36.83 − 40 × 36 = 70 years.

37. What is the average of the 5 consecutive odd numbers starting from 33?

  1. 46
  2. 44
  3. 39
  4. 37
Answer

D. 37 Average of an arithmetic sequence = (first + last)/2 = (33 + 41)/2 = 37.

38. Find the average of 23, 30, 54, 66.

  1. 43.25
  2. 47.58
  3. 34.6
  4. 42.25
Answer

A. 43.25 Sum = 173, count = 4, average = 173/4 = 43.25.

39. Find the average of 26, 54, 98, 78, 18, 33.

  1. 49.17
  2. 63.96
  3. 53.17
  4. 51.17
Answer

D. 51.17 Sum = 307, count = 6, average = 307/6 = 51.17.

40. Find the average of 75, 94, 36, 16, 64, 65, 87.

  1. 49.94
  2. 62.43
  3. 46.82
  4. 56.19
Answer

B. 62.43 Sum = 437, count = 7, average = 437/7 = 62.43.

41. The average marks of 6 boys is 73 and of 12 girls is 40. What is the average of the whole class?

  1. 51
  2. 46
  3. 50
  4. 52
Answer

A. 51 Total = 6 × 73 + 12 × 40 = 918. Average = 918/18 = 51.

42. The average age of 26 students is 35 years. When the teacher's age is included, the average becomes 36 years. What is the teacher's age?

  1. 62 years
  2. 64 years
  3. 68 years
  4. 78 years
Answer

A. 62 years Teacher = 27 × 36 − 26 × 35 = 62 years.

43. What is the average of the 18 consecutive odd numbers starting from 3?

  1. 15
  2. 22
  3. 21
  4. 20
Answer

D. 20 Average of an arithmetic sequence = (first + last)/2 = (3 + 37)/2 = 20.

44. Find the average of 39, 55, 54, 70.

  1. 54.5
  2. 53.5
  3. 49.05
  4. 68.13
Answer

A. 54.5 Sum = 218, count = 4, average = 218/4 = 54.5.

45. Find the average of 90, 80, 27, 83, 65, 81.

  1. 89
  2. 78
  3. 71
  4. 69
Answer

C. 71 Sum = 426, count = 6, average = 426/6 = 71.

46. Find the average of 26, 21, 17, 74, 70, 36, 39.

  1. 41.43
  2. 40.43
  3. 36.39
  4. 32.34
Answer

B. 40.43 Sum = 283, count = 7, average = 283/7 = 40.43.

47. The average marks of 11 boys is 41 and of 12 girls is 45. What is the average of the whole class?

  1. 43.09
  2. 47.4
  3. 38.78
  4. 34.47
Answer

A. 43.09 Total = 11 × 41 + 12 × 45 = 991. Average = 991/23 = 43.09.

48. The average age of 23 students is 57 years. When the teacher's age is included, the average becomes 56.54 years. What is the teacher's age?

  1. 46 years
  2. 58 years
  3. 45 years
  4. 55 years
Answer

A. 46 years Teacher = 24 × 56.54 − 23 × 57 = 46 years.

49. What is the average of the 8 consecutive odd numbers starting from 57?

  1. 77
  2. 65
  3. 70
  4. 64
Answer

D. 64 Average of an arithmetic sequence = (first + last)/2 = (57 + 71)/2 = 64.

50. Find the average of 61, 59, 45, 27.

  1. 53
  2. 48
  3. 58
  4. 49
Answer

B. 48 Sum = 192, count = 4, average = 192/4 = 48.

51. The average of 17 numbers is 108. If a new number 270 is included, what is the new average?

  1. 120
  2. 115
  3. 117
  4. 107
Answer

C. 117 New total = 1836+270 = 2106; divide by 18.

52. The average of 16 numbers is 92. If a new number 279 is included, what is the new average?

  1. 104
  2. 110
  3. 108
  4. 103
Answer

D. 103 New total = 1472+279 = 1751; divide by 17.

53. The average of 6 numbers is 54. If a new number 152 is included, what is the new average?

  1. 58
  2. 66
  3. 68
  4. 69
Answer

C. 68 New total = 324+152 = 476; divide by 7.

54. The average of 11 numbers is 95. If a new number 143 is included, what is the new average?

  1. 99
  2. 92
  3. 98
  4. 89
Answer

A. 99 New total = 1045+143 = 1188; divide by 12.

55. The average of 19 numbers is 26. If a new number 206 is included, what is the new average?

  1. 37
  2. 28
  3. 35
  4. 42
Answer

C. 35 New total = 494+206 = 700; divide by 20.

56. The average of 8 numbers is 71. If a new number 134 is included, what is the new average?

  1. 79
  2. 68
  3. 78
  4. 80
Answer

C. 78 New total = 568+134 = 702; divide by 9.

57. The average of 10 numbers is 34. If a new number 166 is included, what is the new average?

  1. 51
  2. 46
  3. 36
  4. 39
Answer

B. 46 New total = 340+166 = 506; divide by 11.

58. The average of 3 numbers is 106. If a new number 158 is included, what is the new average?

  1. 116
  2. 119
  3. 118
  4. 120
Answer

B. 119 New total = 318+158 = 476; divide by 4.

59. The average of 10 numbers is 90. If a new number 112 is included, what is the new average?

  1. 92
  2. 89
  3. 95
  4. 85
Answer

A. 92 New total = 900+112 = 1012; divide by 11.

60. The average of 19 numbers is 20. If a new number 140 is included, what is the new average?

  1. 26
  2. 23
  3. 21
  4. 28
Answer

A. 26 New total = 380+140 = 520; divide by 20.

61. The average of 20 numbers is 91. If a new number 280 is included, what is the new average?

  1. 99
  2. 101
  3. 103
  4. 100
Answer

D. 100 New total = 1820+280 = 2100; divide by 21.

62. The average of 13 numbers is 120. If a new number 330 is included, what is the new average?

  1. 133
  2. 125
  3. 135
  4. 136
Answer

C. 135 New total = 1560+330 = 1890; divide by 14.

63. The average of 6 numbers is 99. What is their sum?

  1. 564
  2. 582
  3. 587
  4. 594
Answer

D. 594 Sum = average × count = 99 × 6 = 594.

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